Air-motor jack



July 2 1932.

F. H SCHWERIN ET AL AIR MOTOR JACK Filed May 17. 1930 3 Sheets-Sheet 1 'IN ENTORS f jl M/ v %Z/J%ORNEY July 26, 1932. F. H. SCHWERIN ET AL AIR .MOTOR JACK Filed May 17, 1930 3 Sheets-Sheet 2 y 1932. F. H. SCHWERIN ET AL 1,863,922

AIR MOTOR JACK Filed May 1.7, 1930 3 Sheets-Sheet 3 Patented July 26, 1932 FRANK H. SCHWERIN AND LOUIS HEBBELN,

PATENT OFFICE OF BELLE TUE, PENNSYLVANIA, ASSIGNORS TO THE DUFF-NORTON MANUFACTURING COMPANY, OF PITTSBURGH, PENNSYL- VAN IA, A CORPORATION OF PENNSYLVANIA AIR-MOTOR JACK Application filed lay 17,

In known lifting jacks which are operated by air-motors, the motive fluid is controlled by a reversing throttle valve which is movable in opposite directions by a hand lever tostart the jack either up or down andis automatically restored by the jack itself to a neutral or stop position when the lifting element of the jack reaches the full'raised or full-lowered position.

Various types of air-motors are used in assembly with such'jacks, andheretofore the reversing throttle forming part of the coinlfiercial air-motor has been used as the throttle valve for the jack, connections being provided between this valve and either the gearing or the lifting element of the jack to accomplish the automatic shut-01f of power.

We have found that, for the purposes of such jacks, the regular throttle valves fur- 2 nished on the air-motors are unsatisfactory,

in that they do not shut off completely when the jack has been raised or lowered as far as it should go' for safety, and then leak air, that they resist operation after they are in this use for a short while, due to gumming up, and also that they are not satisfactorily applicable to mechanical connections for antomatic operation by the jack or adapted for a standard form of such control mechanism.

The valve mechanism and the combination thereof with the jack and its motor herein described have been designed to overcome these difficulties and to provide a lifting jack in V which the motive fluid is not only controllable by hand but is also controlled definitely and with certainty by the jack itself. Other objects are to provide a valve mechanism in a separate unit, in such combination with the jack and the motor that the valve mecha-- nism is applicable to all usual types of mo-' tor and to all sizes of jacks, and can be used with a standard or easily modified form of control mechanism.

I It thus becomes practicable to give a customer of the jack manufacturer a choice of the popular makes of air motors for application to the acks which he orders, and affords assurance that the combination which he selects will operate satisfactorily, both manually and automatically. This is a great ad- 1930. Serial No. 453,136.

vantage over standardizing on one make of motor and using the regular valve supplied.

with the motor, such valves being designed throttle valve of a kind which moves easily and will remain in good working condition indefinitely, with an inlet valve to out 01f air from the reversing valve, all as more fully set forth hereinafter. These two valves are interconnected so as to Work in conjunction, and this is advantageously accomplished by provlding or connecting the spindle of the rotary oscillatory reversing valve with a recessed cam which opens the inlet valve when the reversing valve is turned either way from neutral, to cause the jack to move up or down, and which causes the inlet valve to close under spring pressure or the pressure of the motive fluid, or both, when the reversing valve is automatically restored to neutral.

The same cam, or another cam, connected with the reversing valve has two slopes at the sides of a recess, which are acted upon by a positioner, preferably a spring-pressed plunger, to drive the valve mechanism to the precise neutral point, when the plunger is released by the turning of the cam for a certain distance under the action of the jack. The cam is also preferably provided with holding notches which are engaged by the plunger when the valve mechanism is moved by hand to the lifting or the lowering position.

The solution of the problem to which the invention is addressed involves the provision of a duplex connection conduit extending from the air motor which is applied to or incorporated with the lower part of the shell of the jack, at one side. This conduit-contains two ducts through which air is alternately conducted to the motor and exhausted therefrom, for operation of the motor in one direction or the other to raise and lower the jack. To this conduit, and interposed between -the same and a supply conduit the body of the valve is connected. The valve is standard and is .applicable to the various makes of motor, the duplexceive a conventional lever and ratchet mechconnection conduit, however, being preferably interchangeable with others hav ing different bends. The valvebody has two passages to communicate with the ducts of the connection conduit, a supply passage or space, and an exhaust outlet. The reversing valve in this body connects the two communicating passages alternately with the supply passage and with the exhaust outlet, and in neutral position shuts off both communicating passages from the supply passage, so that no air reachesthe motor. As a further safeguard, the reversing valve is interconnected with a poppet inlet valvecontrolling the p y P sa One of the objects of the invention is to guard against damage to the automatic connection or operating the valve from the jack when the lifting .member reaches or aproaches one orboth liliiits of its movement.

eretofore, the automatic shutofi mechanisms devised for use with the valves supp lied with air motors have required operating hnks or connections extending laterally for a considerable distance and in an exposed condition from the shell or standard of'the jick to the valve, and these connectionshave en subjectto injury, with consequent hazard that the jack would not be stopped automatically when it should stop in order to avoid serious accident. The duplex connection conduit forming art of this invention is bent close into the side of the shell, so that a direct vertical connection, not subject to injury, ma' .be used to rate the valve automatica y from the li ing member.

In the accompanying drawings forming part'hereof: Fi 1 is a vertical section of a jack embodying t e invention, the air-motor, the valve and the conduits being in elevation, and a port on of.a guard-plate being broken awa -F1g. 2 is a vertical section through t e valve structure taken on theline 22 of Fig. 1.;

, ig. 3 is a vertical section taken on the line'33' of Fig. 2; I Fig. 4 is a horizontal section on the line 4- 4 of Fig. 1;

Figi5 is a vertical section taken on the 1ine-'55 er Fig. 2; and

Fig. 6 is a horizontal sectlon taken through the lower part of the jack, approximately on the line 6-6 of Fig. 1 the motor and certain other portions being broken away.

The jack illustrated is of the screw type having a base 2, a shell 3 rising therefrom, and a lifting element 4. slidably guided in the shell, t h1s element having a nut 5 which is engaged by a rotary lifting screw 6 supported through a ball-bearing 7 on the base. A bevelfgear 8-is united with the screw and is meshed by a bevel pinion 9 on a horizontal shaft 10, the outer portion 11 ofwhich projects outward from the shell of the jack to reanism for operation of the jack by hand (this portion of the shaft bein broken off in Fig. 6 because of lack of space A worm-wheel 12 is mounted on the shaft so as to be capable of rotating freely thereon, and this wheel can be clutched to the shaft, and thereby to the bevel pinion 9,

or unclutched therefrom, by a sliding clutch element 13, feathered on the shaft and operable by an accessible handpiece 14 which operates a shifter fork 15. This enables the jack screw to be disconnected from the motor for manual operation when desired.

The air-motor 16 ,is applied to the side of the shell of the jack and is bolted in position. The mechanism of the motor has not been shown since it forms no part of the invention and an one of a number of air motors may be emp oyed. The motor delivers its power through a shaft bearing a spur pinion-17 which drives other spur gears of a'reducing train 18 located in a recess 19 in the outer side of the jack shell which is closed by the application of the air-motor casing, and the last shaft of this train carries a worm 20 inside the jack enclosure, which worm meshes with the worm-wheel 12 previously referred to. This'constitutes the drive from the airmotor to the lifting mechanism of the jack.

The valves for controlling flow of compressed air to the motor are containedin a valve body 21, located above the motor and adjacent the side of the jack. This valve body is connected with the air motor bya conduit section 22, which is a duplex conduit having two' ducts 23 and 24 separated by a septum 25 and adapted to serve alternately for intake and exhaust. This conduit isdetachably connected on the one hand to the motor and on the other hand to the valve body, which it supports, and is bent or curved inward toward the shell of the jack so that the valve is close to the shell. When compressed air is supplied to the motor through the duct 23, the motor is operated in the direction to lower the jack, whereas when the air flows in through the duct 24 the motor is opelpated in the reverse direction to raise the ac v 1 The conduit 22 isconnected to the valve body by a coupling 26, and this portion of the-valve body has a septum 27 forming two her 30.

.the exhaust outlet.

chambers 28 and 29 which are in open communication with the ducts 23 and 24 respectively. 4

The inner part of the septum 27 spreads and partially encloses an air supply chainthe valve body at the front of this chamber, this liner having four ports 32, 33, 34, 35. The port 32 communicates with the supply chamber 3-0, the ports 33 and 34 at right angles thereto communicate with the chambers 28 and 29, and the port 35 opens beneath an exhaust hood 36. p

A rotary valve 37 of the Corliss type turns within this liner, the valve having cylindrical bearing portions 38 (Fig. 4) and an intermediate portion 39 slabbed off at both sides. This valve moves through an angle of 90?. In the position shown in Fig. 5, it connects the inlet chamber 30 with the chamber 29 and the conduit duct 24, at the same time connecting the conduit duct 23 and chamber 28 with lVhen this valve is in its other extreme position it connects the chamber 28 and conduit passage 23 with the inlet chamber, and connects the duct 24 and the chamber 29 with the exhaust outlet. In the intermediate or neutral position, 45 away from each extreme position, the valve blanks the port 30 and cuts off the supply of air to either duct 23 or 24.

But even though thiseasy operating valve should not be absolutely tight in the neutral position, when the motor is at rest and the lifting member of the jack has stopped at either the upper or the lower limit of its motion, or has been stopped at any intermediate position, leakage of air is prevented. For this purpose an inlet valve 40 of the poppet type is provided, the disc of this valve operating in a chamber 4l-of an extension 42 of the valve body, which extension is con: nected with a supply conduit 43 which is connected with the compressed air hose line. This valve seats on and its stem 44 is guided in a bushing 45, which is cut away to permit the compressed air to pass freely to a space 46, which is in direct communication with the supply chamber 30 already referred to.-

The inlet valve is preferably urged to its seat by a spring 67, in addition to which it is urged closed and held closed by the pressure of the air.

There is an interconnection between the two valves which have been described, so that when the reversing throttle valve 39 is in either of its open positions the inlet valve 40 is likewise open, and whenthe reversing valve is in neutral position the inlet valve is closed.

The bod Y of the stem of the oscillatory reversing va ve has 'a cam 47 which is formed with a wide V recess 48. When the reversing valve is in neutral position, the bottom of this recess is in line with the stem 44. of the inlet valve, and the recess is deep enough so that A cylindrical liner 31 is fitted into cam has another wide V recess 49 to cooperate with a spring-pressed plunger 50 which is guided in a bore of the valve body. This plunger acting in connection with the reversely sloping sides of the recess 49 not only serves to hold the reversing valve non-positively in neutral position, but to force it to that position. \Vhen the reversing valve 37 is in either of its extreme positions, for movement up or down of the jack, the plunger bears on the cam at one side or the other of the recess 49, and preferably then engages with one of two rounded holding notches 51. When the reversing valve is turned a certain distance from either of these positions toward the neutral or mid-position, and the high point of one or other of the cam slopes formed by the'sides of the recess 49 passes the center of the plunger, the pressure of the plunger then acting on such slope throws the reversing valve to the neutral position, and there stops it. When the reversing valve is turned in either direction away from its neutral posi- 'tion,'one slope or the other of the recess 49 cams the plunger away from the axis of the cam until it finally drops into one of the recesses 51. This positioning and actuating device controls the closing of the inlet valve 40 in addition to bringing the reversing valve to its neutral position, this being due to the interconnection between the valves which has been described.

The spindle of the reversing valve has a shaft portion 52, which projects through a bearing in the side of the valve body, and to its end is fixed a hand lever 53 which is movable behind a guard plate 54, the latter bearing on its face Up, Stop and Down designations as shown in Fig. 1. By means of this handle, the reversing throttle valve is moved from neutralposition to either the The recesses are engageable bya spring-,

pressed plunger or dog 58 in a fitting 59 on a rod 60. The position of this control rod is vertical, that is to say parallel with the liftingelement, and it is guided in bearing openings in an extension 61 projecting fromthe top of the shell 3 of the jack. The lower end of the rod carries a lateral pin 62 which lies inan elongated slot 63 in an arm 64, which arm isconnected with the spindle of the reversing valve and preferably integral with the hand lever 53.

The drawings illustrate the condition at the moment when the hand lever has been moved to the Up position, causing air to passto and through the motor in the direction to raise the lifting element 4 and the load "which may rest thereon. The lifting element is shown all the way down, just at the instant of starting upward.

The recess 55 in the side of the lifting element is to be so located that it comes into engagement with the dog 58 at about the extreme point of the raise which is considered permissible. The abrupt shoulder 56 then raises the dog, thereby raising the rod 60 and causing the pin62 acting against one end of the slot 63 to move the reversing valve 37 toward neutral position. When the high point of one or the other of the sloping sides of the recess 49 of the cam 47 passes the cen- 4 ter of the extremity of the plunger 50, this spring-actuated element takes control and.

cams the reversing valve to exact neutral position. At the same time the recess 48 of the cam is brought beneath the' stem of the 50 inlet valve 40, and this valve closes.

The handle 53 is then in the Stop position. To cause the lifting element to move downward, the operator moves the handle to the Down position, thereby moving the reversing valve to the corresponding position and re-opening the inlet-valve. When the lifting element has descended almost to its lowest position, the shoulder of the recess 55 acts on the dog 58 to push the rod 60 downward, thereby turning the reversing valve37 back to neutral and causing the inlet valve 40 again to close. The handle 53 is'then once more in the Stop position.

- In the neutral or stop position of the valve 37, which is shown in dotted lines in Fig. 5,

the inlet port 32 is completely coveredbut the exhaustport 35 is not entirely closed.

The purpose of this is to vent any leakage past the poppet valve 'and the reversing valve, if there should be any leakage, so as to avoid any possibility of the jack being operated when the-valve is in the neutral position.

After the lifting element of the jack has moved the valve to neutral position, the valve can not be returned to a position to operate the motor and jack in the direction from which it has just been shut elf. This is due to the abrupt sides of the notches 55, blocking movement of the dog 58 and rod 60,

the latter in turn blocking movement of the hand lever 53. Therefore, after theend of the stroke in either direction, the jack can 1 then be operated only in the reverse direction. lVhile the preferred embodiment of the invention has been described in detail, it will be understood that various changes may be made without departing from essentials.

lVe claim:

1. Thecombination with a lifting jack and an air-motor for operating the same, a conduit extending from the motor and containingtwo ducts for conducting air to said motor to operate the same to raise or lower the jack, a supply conduit, an oscillatory reversing valve interposed between said supply conduit and said ducts, a poppet valve in said supply conduit, a cam portion connected with said oscillatory valve and cooperating with the stem of said poppet valve so that the poppet valve closes'when the reversing valve comes to neutral position and is opened when the oscillatory valve is turned in either direction from neutral position, a handle for turning said oscillatory valve, and means controlled by the jack for automatically turning the oscillatory valve to neutral position.

2. The combination with a lifting jack and an air-motor for operating the same, a conduit extending from the motor and containing two ducts for conducting air to said motor to operate the same to raise or lower the jack, a supply conduit, an oscillatory reversing valve interposed between said supply conduit and said ducts, a poppet valve in said supply conduit, a cam portion connected with said oscillatory Valve and cooperating with the stem of said poppet valve so that the poppet valve closes when the reversing valve comes to neutral position and is opened when the oscillatory valve is turned in either direction from neutral position, a handle for turning said oscillatory valve, a slotted arm connected with said oscillatory valve, a dogcooperating with the lifting member of the jack, a movable rod with which said dog is connected, and a projection connected with said rod {and cooperating with said slotted arm to move said oscillatory valve toward neutral position.

' 3. The combination with a lifting jack and an air-motor for operating the same, a conduit extending from the motor and contalnmg two-duets for conducting air to said motor'to' operate the same to raise or lower "the ack, a supply conduit,- an oscillatory reversing valve interposed between said supply conduit and said ducts,'a poppet valve 111 said supply condu t, a cam portion connected with said oscillatory valve and cooperating with the stem of said poppet valve so that the poppet valve closes when the reversing valve comes to neutral position and is opened when the oscillatory valve is turned in either direction from neutral position, a handle for turning said oscillatory valve, means operated by the jackfor turning said oscillatory valve toward neutral position,- and means then active to bring said oscillatory valve to neutral position. v

4. The combination with a lifting jack and an air-motor for operating the same, a conduit extending from the motor and containing two ducts for conducting air to said motor to operate the same to raise or lower the jack, 9. supply conduit, an oscillatory reversing valve interposed between said supply conduit and said ducts, a poppet valve in said ated by the jack for turning said oscillatory valve toward neutral position, a secondv cam portion connected with'sald oscillatory valve having a recess with reversely sloplng sides,

and a spring actuated plunger adapted .to

cooperate with said sloping sides to restore the valve to neutral position.

5. The combination with a lifting jack an an air-motor for operating the same, a con duit extending from the motor and containing two ducts for conducting air to said motor to operate the same to raise or lower the jack,

a supply conduit; an oscillatory reversing valve interposed between said supply conduit and said ducts, a poppet valve in said supply conduit, a cam portion connected with said oscillatory valve and cooperating with the I stem of said poppet valveso that the poppet valve closes when the reversing valve comes to neutralposition and is opened when the oscillatory valve is turned in either direction from neutral position, a handle for turning said oscillatory valve, means operated by the jack for turning said oscillatory valve toward neutral posltion, a second cam portion eonnected with said oscillatory valve having a recess with reversely sloping sides and a holding notch at either side of said recess, and a spring-actuated plunger adapted to cooperate with said holding notches to hold said valve in its extreme positions and also with said sloping sides to restore the valve to neutral position.

6. The combination with a lifting jack and an air-motor for operating the same, an OS cillatory valve controlling flowof air to said motor to operate the same to raise or lower the jack, ahandle for moving said valve in. either direction from neutral position, means operated by the jack for turning said oscillatory valve toward neutral position, and a spring-actuated positioner adapted to bring said oscillatory valve to neutral position.

-7. The combination with a lifting jack and an air-motor for operating the same, an oscillatory valve controlling flow of air to said motorto operate the same to raise or lower the jack, a handle for moving said valve in either direction from neutral position, means operated by the jack for turning said oscillatory valve toward neutral position, a cam portion connected with said valve and having a recess with reversely sloping sides, and a spring-actuated plunger adapted to cooperate with the sides of said recess to bring said valve to neutral position.

8. The combination with a lifting ack and an air-motor for operating the same, an oscillatory valve controlling flow of air to said motor to operate the same to raise or lower the jack, a handle for moving said valve in either direction from neutral position, means operated by the jack for turning said oseillatory valve toward neutral position, a cam portion connected with said valve and having a recess with reversely sloping sides and a holding notch at either side of said recess, and a spring-actuatedplunger adapted to cooperate with said holding notches to hold said valve'in its extreme positions andralso with said sloping sides to bring said valve to new tral position.

9. The combination with a lifting jack and an air-motor for operating the same, valve mechanism controlling flow of air to said motor to operate the same to raise or lower the jack, a-handle for moving said valve mechanism in either direction from neutral, means operated by the jack toward the end of its raising or lowering movement to start I said valve mechanism toward neutral condition, and a positioner for completingthe return of said valve mechanism to neutral condition independently .of further movement of the jack. v

10. The combination with a lifting 'aek andan air-motor united to the frame of the ack and geared to the lifting element thereof, of a separate valve unit comprising a valve body, a duplex conduit connecting said valve body with said air-motor, an inlet conduit connected with another part of said body, a reciproeatory inlet valve in-theinlet passage of, the body, an oscillatory reversing valve in said body between said inlet valve and the passages of said duplex conduit, a mechanical interconnection between said valves adapted to cause said reciprocatory inlet valve to close when the reversing valve comes to neutral position and to openv when the oscillatory valve is turned in either direction from neutral position, a handle for operating the reversing valve, and an automatic 'control linkage between said oscillatory valve and a movable part of the jack.

11. In an air-motor jack, the combination with the jack of a reversing valve'having two positions in which it controls the flow of air to raise and lower the lifting member, re spectively, and a neutral stop position, a handle for operating said reversing valve, linkage adapted to be operated by a movable part of the jack to start said reversing valve toward its neutral position under .actuation by the jack, means then operative to bring said valve to the neutral position, and a device interconnecting said valves so that the inlet valve is opened when the reversing valve is moved to either of its extreme positions and closes when the reversing valve is moved to neutral position.

12. The combination with a lifting jack and an air-motor for operating the same, a connection conduit extending from the motor and containing two ducts for alternately conducting air to said motor and exhaust air therefrom, for operation of the motor in either direction to raise or lower the jack, a valve body applied to said conduit and containing two passages communicating with the ducts in said connection conduit, a supply passage and an exhaustoutlet, an oscillatory reversing valve in said body adapted to connect said communicating passages alternately with the supply passage and with the exhaust outlet, a poppet valve in said supply passage, a cam portion connected with said oscillatory valve and cooperating with the stem of said poppet valve so that the poppetvalve closes whenthe reversing valve comes to neutral position and is opened when the oscillatory valve is turned in either direction fromneutral position, a handle for turning said oscillatorv valve, and means controlled bvthe jack for automatically turning i the oscillatory valve to neutral position.

,13. The combination with a lifting jack having a shell, a lifting element guided in the top of said shell, and a lifting screw cooperating with said lifting element, of an air motor connected withthe lower part'of said shell and geared to said screw, a conduit rising from said motor and extending inward toward the shell, said conduit containing two ducts for alternately conducting air to the motor and exhaust air therefrom, a valve body applied tosaid conduit in close proximity to the shell, said valve body hav- 7 mg two'passages communicating with said,

ducts. a supply passage and an exhaustoutoperating with saidlifting element, of an air motor connected with the lower'part of saidshell and. geared to said screw, :1 conduit rising from said motor and. extending inward toward the shell, said conduit containing two ducts for alternately conducting air to the motor and exhaust air therefrom, a valve body applied to said conduit in close proximity to the shell, said valve body having two passages communicating with said ducts, a supply passage and an exhaust outlet, an oscillatory reversing valve in said body adapted to connect said communicating passages alternately with the supply passage and the exhaust outlet, a handle for operating said valve manually, a vertical rod having operative connection with said valve, and means on said lifting element to operatesaid rod. 7

- FRANK H. SCHWERIN.

LOUIS HEBBELN. 

